This invention relates generally to packaging and package conveying systems and, more particularly, to a method and apparatus for package labeling wherein a labeler is moved horizontally relative to a package to be labeled to thereby more accurately position labels within selected labeling regions on packages processed and/or conveyed by the systems. This invention is particularly applicable to integrated packaging systems, including a wrapping machine, a weighing scale and a labeler, and hence, will be primarily described with reference to such integrated packaging machines.
A number of package wrapping machines are well known and used, for example, in supermarkets for packaging meats, produce and other food items. Such wrapping machines may provide at least two different widths of wrapping material to accommodate a large variety of package sizes. The wrapping material is provided in continuous rolls of different widths such that the length and width of sheets of wrapping material may be selected for wrapping packages. The length and width of a sheet of wrapping material to be used for a given package may be selected by the operator based on the package to be wrapped or may be automatically selected based on machine-sensed dimensions of the package.
Computing weighing scales and labelers which print and apply price labels to packages are oftentimes associated with wrapping machines. A computer or other electronic means is included within the scale or labeler for calculating prices for the packages. Prices are calculated by multiplying the net weight of a package times the price per unit weight of the commodity within the package, the unit price having been previously stored into a memory of the computer. Commodity net weight is determined by compensating for the tare weight or weight of the packaging material.
In the operation of a prior art packaging system, a commodity to be packaged is initially placed onto a supporting tray. The trayed commodity or package is then fed into the wrapping machine where a sheet of packaging material, typically transparent stretch film, is wrapped about the package and secured beneath the tray. The wrapped package is then conveyed either mechanically or manually to a combination scale and labeler. At the scale and labeler, the price of the package is computed, a price label is printed and the label is applied to the package.
In order to conserve space, packaging systems have combined a weighing scale, a wrapping machine and a label printer into a single unit. See, for example, Teraoka, U.S. Pat. No. 4,415,048, wherein a trayed commodity is initially placed onto a weighing scale which forms the input of a wrapping machine. The trayed commodity is weighed, wrapped and passed to a package outlet passage along which a labeler is positioned to generate a pricing label and apply the label to the wrapped package. In the Teraoka packaging system, labels are printed and applied downstream from the wrapping station along a wrapped package outlet passage such that labeling information must be stored and delayed or large gaps must be placed between consecutive packages for labels to correspond correctly to wrapped packages.
The heights of packages passing through the Teraoka packaging system are measured such that the label applying apparatus may be shifted vertically to accommodate varying heights of packages. Packages to be labeled are positioned beneath the package labeling apparatus by means of guide plates which position the packages laterally or both laterally and longitudinally. Package shifting for label positioning is also effected along a package outlet passage in an integrated packaging machine disclosed in Fine, U.S. Pat. No. 4,458,470.
To overcome the problems created by having to store and delay the weight signals of packages or the packages themselves progressing through a packaging machine, an improved packaging system is disclosed in Boshinski, U.S. Pat. No. 4,543,766 which is incorporated herein by reference. In the Boshinski packaging system, the wrapping machine is an elevator-type machine presently quite popular in the supermarket industry. A labeler is positioned over the elevator and a weighing conveyor extends between a package feed-in tray and the elevator such that a package is weighed as it is conveyed to the elevator, a label is printed and applied to the package as the package is wrapped by elevation into a sheet of wrapping material.
While the Boshinski packaging system eliminates the necessity of large gaps between consecutive packages or delaying the scaled weights of packages within the machine and also the need for vertically shifting the labeler to accommodate varying heights of packages, it is impossible to provide the package positioning guide rails or other package shifting apparatus for selectively positioning labels upon packages processed by the system. This shortcoming may be very important to a supermarket since it is oftentimes desirable to be able to position a pricing label in a specified portion of the package, typically near a corner, such that packages may be attractively displayed and permit the consumer to readily read the price of individual packages from a normal viewing position. Hence, the need exists for label positioning on packages where it is impossible or undesirable to shift the package itself, for example, within integrated packaging systems such as the Boshinski system disclosed in above-referenced U.S. Pat. No. 4,543,766.